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排序方式: 共有647条查询结果,搜索用时 15 毫秒
71.
72.
Parent material composition, particle disintegration by glaciers and lacustrine environment govern the geological development
and engineering characteristics of clay deposits in southern Saskatchewan. The pre-existing expansive clay minerals were preserved
due to the restrained leaching in the Regina Lake and the prevalent aridity in the area. The main objective of this paper
was to develop a fundamental understanding of the clay deposit for the use in the design and construction of civil infrastructure.
The results indicated the presence of expansive clay minerals in the deposit, with smectite accounting for 35% of the material.
The major exchangeable cation was found to be Ca2+ which accounted for more than half of the total measured cation exchange capacity of 40 (cmol(+)/kg). The most likely exchange
complex governing water adsorption of the clay was determined to be Ca2+-smectite. Alongside a high initial saturation (86%), this complex resulted in moderate volume changes in the clay. The swelling
pressure was fully developed within the first hour of the constant volume test. The corrected swelling pressure was determined
to be 120 kPa leading to an estimated heave of 36 mm in the surface layer of the deposit. The compression index and the swelling
index were found to be 0.25 and 0.08, respectively. 相似文献
73.
Ali Aakash Nasir Muhammad Ali Khalid Muhammad Yasir Nauman Saad Shaker Khubab Khushnood Shahab Altaf Khurram Zeeshan Muhammad Hussain Azhar 《Journal of Mechanical Science and Technology》2019,33(9):4217-4226
Journal of Mechanical Science and Technology - Natural fiber composites have great potential for reducing the product cost, lowering weight and enhancing renewability. Functionality and performance... 相似文献
74.
Norshahirah Mohamad Saidi Hong Ming Ng Fatin Saiha Omar Shahid Bashir K. Ramesh S. Ramesh 《应用聚合物科学杂志》2019,136(32):47810
New gel polymer electrolytes (GPEs) were prepared via the blending of a polyacrylonitrile polymer and a poly(1-vinyl pyrrolidone-co-vinyl acetate) copolymer. The sodium iodide (NaI) salt concentration was varied for each GPE sample. From ionic conductivity (σ) studies, we observed that the sample with a 40 wt % NaI salt content (N40) showed the highest σ of 3.54 × 10−3 ± 0.05 S/cm at room temperature, and all of the GPE samples obeyed Arrhenius behavior. The dielectric properties of the GPE samples were also analyzed to study the electrical polarization of the materials. The developed GPE samples were also characterized with X-ray diffraction and Fourier transform infrared spectroscopy. We also then used the developed GPE samples for the fabrication of dye-sensitized solar cells by sandwiching them between a photoanode and Pt counter electrode for photovoltaic studies. The highest photovoltaic performance was achieved by N40, with an efficiency of 3.04%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47810. 相似文献
75.
Shabnum Shaheen Muhammad Asaf Khan Muhammad Afzal Naeem Muhammad Naveed Shahid Mehwish Jaffer Hanan Mukhtar 《Microscopy research and technique》2022,85(3):1194-1198
The anatomical variations of two plants from the Nyctaginaceae family, Bougainvillea spectabilis and Bougainvillea glabra, were studied using light and scanning electron microscopy methods in this work. Bougainvillea is a dicotyledonous with defensive traits that can withstand extreme (hot and dry) settings; according to the findings, crystal inclusions in cells, woody spines, and an abnormal development pattern are all features that help them survive against predators and are unique to this species. The Bougainvillea plant's leaves are arranged in simple pattern, alternate to each other along stem having an undulate leaves edge and an oval form. The xylem and phloem, palisade, parenchyma midrib, spongy mesophyll, raphide crystal bundles, and trichomes were all visible when bracts and leaves were transversally sectioned and dyed with toluidine blue O (TBO). The presence of crystals was confirmed by a detailed examination of the transverse leaves by using bright-field and cross-polarizing microscopy. Dissecting microscopic examination showed that all the leaves revealed leaves venation pattern that had midvein, lateral veins areoles, and trichomes. Although trichomes have been identified on both sides, a closer look at a cleaned leaf dyed with TBO showed multicellular abundant trichomes on adaxial surface. Stomata complexes were typically found on the abaxial surface of the leaf according to epidermal peels. Present studies also showed that on adaxial side, stomata were lesser in number or were absent and also showed that the morphologies of the pavement cells on the adaxial and abaxial sides of the leaf differed. 相似文献
76.
Bilal Shahid Dangqiang Zhu Qian Wang Xiyue Yuan Irfan Ismail Yao Wu Zurong Du Renqiang Yang 《Polymer International》2020,69(6):564-570
To optimize the energy levels of the structural framework of isoindigo polymers, a series of asymmetric isoindigo based low bandgap polymers with chlorine, fluorine and thiazole substituents was constructed and their optical, electrochemical and photovoltaic properties were comparatively evaluated for the impact of different substitutions. In comparison with the polymer based on 2,2'‐bithiophene and isoindigo unit (PTi) with non‐substituted bithiophene as the donor moiety, the highest occupied molecular orbital energy level for the newly synthesized polymers is significantly decreased, and in turn an improvement of the open‐circuit voltage (VOC) is noted in the corresponding photovoltaic devices. More importantly, combined with a low bandgap of 1.32 eV, the energy losses (Eloss) could be reduced to 0.61 eV for polymer based on chlorinated 2,2'‐bithiophene and isoindigo unit (PCl). In addition, the halogen moieties are observed to be superior in device fabrication and give better values than the thiazole substituent. Both fluorinated and chlorinated polymer donors exhibited improved performance compared with the original polymer PTi. Consequently, this work not only presents the influence of different electron withdrawing substituents on the physicochemical and photovoltaic performance, but also backs the concept of how to reduce the energy loss via the heteroatom effect. © 2020 Society of Chemical Industry 相似文献
77.
78.
79.
Shahid Hussain Xiaoguang Wang Shabbir Ahmad Muhammad Riaz 《Quality and Reliability Engineering International》2020,36(3):910-946
Monitoring of any manufacturing, production, or industrial process can be controlled and improved by removing these special cause of variations using control charts. Shewhart-type control charts are effective to control a large amount of special variations, whereas, cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) charts detect small and moderate variations efficiently in the process parameters. Monitoring of location parameter can be done with mean control charts under the assumption that the parameters are known or correctly estimated from in-control samples and data are free from outliers (but in practice data occasionally have outliers). In this study, we have proposed generalized mixed EWMA-CUSUM median control charts structures for known and unknown parameters based on auxiliary variables for detecting shifts in process location parameter. The proposed charts are compared with the corresponding charts for the mean, based on contaminated and uncontaminated data. Different performance measures are used to evaluate the performance of proposed control charts and revealed through results that the median-based charts are more sensitive to detect a shift in process location parameter in the presence of outliers. An illustrative example using real data is also shown for practical consideration. 相似文献
80.
Sharafati Ahmad Doroudi Siyamak Shahid Shamsuddin Moridi Ali 《Water Resources Management》2021,35(11):3649-3677
Water Resources Management - This study proposes a new stochastic approach for optimizing diversion system design and its construction schedule by considering different hydrological and hydraulic... 相似文献